The invention relates to a glass sorting apparatus, that is, to the separating arrangement of a glass sorting apparatus for sorting out of a glass mixture parts which do not consist of glass or glass to which non-glass parts are adhering.
With the growing environmental conscientiousness and the growing desire to save energy, it is increasingly considered desirable to recycle used materials. This is also true for glass which is actually a valuable waste material and which is manufactured with the consumption of a relatively large amount of energy. Waste and scrap glass are already being collected for recycling procedures. However, glass is generally received by the recycler in the form of fragments or as bottles which are heavily soiled and, in any case, mixed with other undesirable materials which need to be removed before re-melting. Generally, the glass also must be sorted on the basis of its color. The invention relates to such a sorting process in which undesirable parts or fragments are removed from the glass mixture before recycling.
Especially objectionable in the glass mixture are ceramics or stoneware but those materials are present to a large measure since the consumer providing the glass scrap and the glass scrap collectors erroneously consider glass, ceramics and stoneware to be the same in principle. Also, metal parts are impurities which are frequently present in the form of cemented metal foils or screw caps or other closure devices. Paper labels on the other hand are not particularly objectionable since they, as well as some organic material components, are easily combustible.
In order to remove the objectionable materials from the glass mixture, the glass mixture is generally spread onto a conveyor belt and parts having such objectionable materials associated therewith are normally removed from the conveyor belt. Although machine glass sorting processes have been tried and tested, the tests did not lead to success. The reasons for the failures are that on one hand the objectionable parts could not be properly recognized and distinguished by the sensing equipment utilized and in addition they could not be adequately separated and removed from the mixture.
As a recognition procedure, transillumination by exposure to light may readily be taken into consideration since all the objectionable materials are opaque. It is pointed out however that also paper and accordingly glass with paper cemented thereon is opaque and such glass would therefore be discarded although it could be utilized as pointed out above. Considering that a large part of the glass parts is provided with labels, a large amount of glass would be unnecessarily discarded.
It is therefore the object of the present invention to provide a glass separating apparatus capable of removing from the recycle glass mixtures the undesirable parts but not the glass parts provided with paper labels which are usable for recycling.